Hybrid varifocal lens

Abstract

A hybrid lens is disclosed including optically coupled varifocal lens and adaptive lens. The varifocal lens is configured for varying optical power of the hybrid lens, and an adaptive lens includes a voltage-controlled element for varying optical power of the adaptive lens in coordination with varying the optical power of the varifocal lens and responsive to variation of the optical power of the hybrid lens, for lessening an optical aberration of the hybrid lens. The hybrid lens may be used in head-mounted displays e.g. for lessening a vergence-accommodation conflict.

What is claimed is: 
     
       1. A hybrid lens apparatus comprising:
 a hybrid lens comprising a varifocal lens for varying optical power of the hybrid lens, and a multifocal lens optically coupled to the varifocal lens and comprising a voltage-controlled element for switching optical power of the multifocal lens; and 
 a controller operably coupled to the varifocal and multifocal lenses and configured to vary optical power of the varifocal lens in coordination with switching the optical power of the multifocal lens, thereby lessening an optical aberration of the hybrid lens as the optical power of the hybrid lens is varied; 
 wherein the controller is configured to adjust optical power of the hybrid lens within predefined optical power sub-ranges, wherein each optical power value of the multifocal lens corresponds to a particular one of the predefined optical power sub-ranges of the hybrid lens. 
 
     
     
       2. The hybrid lens of  claim 1 , wherein the varifocal lens comprises a liquid lens comprising a pair of immiscible fluids separated by a boundary having a voltage-variable radius of curvature for varying optical power of the liquid lens. 
     
     
       3. The hybrid lens of  claim 1 , wherein the multifocal lens comprises at least one of: a Pancharatnam-Berry phase (PBP) lens; a polarization volume holographic liquid crystal (LC) lens; or an LC Fresnel lens; and wherein a substrate of the multifocal lens comprises at least one of: a glass substrate; a plastic substrate; or a sapphire substrate. 
     
     
       4. The hybrid lens of  claim 3 , wherein the multifocal lens comprises the PBP lens comprising at least one of: a nano-patterned birefringent structure; or a polymer-embedded LC layer. 
     
     
       5. The hybrid lens of  claim 1 , wherein the voltage-controlled element comprises a first active PBP lens. 
     
     
       6. The hybrid lens of  claim 5 , wherein the multifocal lens further comprises a first switchable polarization rotator optically coupled to the first active PBP lens. 
     
     
       7. The hybrid lens of  claim 6 , wherein the multifocal lens further comprises a second active PBP lens and a second switchable polarization rotator optically coupled to the second active PBP lens. 
     
     
       8. The hybrid lens of  claim 7 , wherein the first and second switchable polarization rotators each comprise an LC switchable half-wave waveplate. 
     
     
       9. The hybrid lens of  claim 1 , wherein the multifocal lens is disposed in an optical path downstream of the varifocal lens. 
     
     
       10. The hybrid lens apparatus of  claim 1 , wherein the varifocal lens comprises a liquid lens comprising a pair of immiscible fluids separated by a boundary having a voltage-variable radius of curvature for varying optical power of the liquid lens; and wherein the controller is configured to vary the radius of curvature of the boundary by varying a voltage applied to the liquid lens in coordination with varying a voltage applied to the voltage-controlled element of the multifocal lens, thereby lessening the optical aberration of the hybrid lens as the optical power of the liquid lens is varied. 
     
     
       11. The hybrid lens apparatus of  claim 10 , wherein the controller is configured to increase the optical power of the multifocal lens when increasing the optical power of the liquid lens, and to decrease the optical power of the multifocal lens when decreasing the optical power of the liquid lens. 
     
     
       12. The hybrid lens apparatus of  claim 1 , wherein the multifocal lens comprises an LC PBP lens, and wherein the voltage-controlled element comprises a voltage-controlled polarization rotator. 
     
     
       13. The hybrid lens apparatus of  claim 1 , wherein the varifocal lens has optical power variable between 4 Diopter and 6 Diopter, and wherein the multifocal lens has optical power switchable between −6 Diopter and −6.5 Diopter. 
     
     
       14. The hybrid lens apparatus of  claim 1 , further comprising an eye tracking system for determining a gaze convergence angle of eyes of a user, wherein the controller is operably coupled to the eye tracking system to adjust the optical power of the hybrid lens responsive to the gaze convergence angle determined by the eye tracking system.